From TFwiki:
Hellflame Gul (Starscream's Micron) - purchase of Darkness Megatron at Ion stores on that toy's release date, July 28
Hellflame Jida (Terrorcon Cliffjumper's Micron) - purchase of 3000 yen's worth of Transformers at Joshin and Bic Camera stores on July 28
Hellflame Noji (Vehicon's Micron) - purchase of 3000 yen's worth of Transformers at Yamada Denki, Yodobashi Camera, and stores in the EDION group on July 28
Hellflame Zamu (Breakdown's Micron) - purchase of 3000 yen's worth of Transformers at Japanese ToysЯUs stores on July 28